8-Hydroxyquinoline

8-Hydroxyquinoline
Names
	Preferred IUPAC name Quinolin-8-ol
	Other names 1-Azanaphthalene-8-ol, Fennosan H 30, Hydroxybenzopyridine, Oxybenzopyridine, Oxychinolin, Oxyquinoline, Phenopyridine, Quinophenol, Oxine, 8-Quinolinol
Identifiers
CAS Number	148-24-3 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:48981 ;
ChEMBL	ChEMBL310555 ;
ChemSpider	1847 ;
ECHA InfoCard	100.005.193
KEGG	D05321 ;
PubChem CID	1923;
UNII	5UTX5635HP ;
CompTox Dashboard (EPA)	DTXSID5020730 ;
	InChI InChI=1S/C9H7NO/c11-8-5-1-3-7-4-2-6-10-9(7)8/h1-6,11H Key: MCJGNVYPOGVAJF-UHFFFAOYSA-N ; InChI=1/C9H7NO/c11-8-5-1-3-7-4-2-6-10-9(7)8/h1-6,11H Key: MCJGNVYPOGVAJF-UHFFFAOYAG;
	SMILES C1=CC2=C(C(=C1)O)N=CC=C2;
Properties
Chemical formula	C9H7NO
Molar mass	145.16 g/mol
Appearance	White crystalline powder
Density	1.034 g/cm3
Melting point	76 °C (169 °F; 349 K)
Boiling point	276 °C (529 °F; 549 K)
Pharmacology
ATC code	G01AC30 (WHO) A01AB07 (WHO) D08AH03 (WHO) R02AA14 (WHO)
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H317, H318, H360D, H410
Precautionary statements	P202, P273, P280, P301+P310, P302+P352, P305+P351+P338
Safety data sheet (SDS)	External MSDS
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

8-Hydroxyquinoline (also known as oxine) is an organic compound derived from the heterocycle quinoline. A colorless solid, its conjugate base is a chelating agent, which is used for the quantitative determination of metal ions.

In aqueous solution 8-hydroxyquinoline has a pK_a value of ca. 9.9^[1] It reacts with metal ions, losing the proton and forming 8-hydroxyquinolinato-chelate complexes.

The aluminium complex,^[3] is a common component of organic light-emitting diodes (OLEDs). Substituents on the quinoline ring affect the luminescence properties.^[4]

In its photo-induced excited-state, 8-hydroxyquinoline converts to zwitterionic isomers, in which the hydrogen atom is transferred from oxygen to nitrogen.^[5]

^ Albert, A.; Phillips, J. N. (1956). "264. Ionization Constants of Heterocyclic Substances. Part II. Hydroxy-Derivatives of Nitrogenous Six-Membered Ring-Compounds". Journal of the Chemical Society (Resumed). 1956: 1294–1304. doi:10.1039/JR9560001294.
^ Cölle, M.; Dinnebier, R. E.; Brütting, W. (2002). "The structure of the blue luminescent δ-phase of tris(8-hydroxyquinoline)aluminium(III) (Alq₃)". Chemical Communications. 2002 (23): 2908–9. doi:10.1039/b209164j. PMID 12478807. S2CID 96135270.
^ Katakura, R.; Koide, Y. (2006). "Configuration-Specific Synthesis of the Facial and Meridional Isomers of Tris(8-hydroxyquinolinate)aluminum (Alq₃)". Inorganic Chemistry. 45 (15): 5730–5732. doi:10.1021/ic060594s. PMID 16841973.
^ Montes, V. A.; Pohl, R.; Shinar, J.; Anzenbacher, P. Jr. (2006). "Effective Manipulation of the Electronic Effects and Its Influence on the Emission of 5-Substituted Tris(8-quinolinolate) Aluminum(III) Complexes". Chemistry: A European Journal. 12 (17): 4523–4535. doi:10.1002/chem.200501403. PMID 16619313.
^ Bardez, E.; Devol, I.; Larrey, B.; Valeur, B. (1997). "Excited-State Processes in 8-Hydroxyquinoline: Photoinduced Tautomerization and Solvation Effects". The Journal of Physical Chemistry B. 101 (39): 7786–7793. doi:10.1021/jp971293u.

[1] Albert, A.; Phillips, J. N. (1956). "264. Ionization Constants of Heterocyclic Substances. Part II. Hydroxy-Derivatives of Nitrogenous Six-Membered Ring-Compounds". Journal of the Chemical Society (Resumed). 1956: 1294–1304. doi:10.1039/JR9560001294.

[2] Cölle, M.; Dinnebier, R. E.; Brütting, W. (2002). "The structure of the blue luminescent δ-phase of tris(8-hydroxyquinoline)aluminium(III) (Alq₃)". Chemical Communications. 2002 (23): 2908–9. doi:10.1039/b209164j. PMID 12478807. S2CID 96135270.

[3] Katakura, R.; Koide, Y. (2006). "Configuration-Specific Synthesis of the Facial and Meridional Isomers of Tris(8-hydroxyquinolinate)aluminum (Alq₃)". Inorganic Chemistry. 45 (15): 5730–5732. doi:10.1021/ic060594s. PMID 16841973.

[4] Montes, V. A.; Pohl, R.; Shinar, J.; Anzenbacher, P. Jr. (2006). "Effective Manipulation of the Electronic Effects and Its Influence on the Emission of 5-Substituted Tris(8-quinolinolate) Aluminum(III) Complexes". Chemistry: A European Journal. 12 (17): 4523–4535. doi:10.1002/chem.200501403. PMID 16619313.

[5] Bardez, E.; Devol, I.; Larrey, B.; Valeur, B. (1997). "Excited-State Processes in 8-Hydroxyquinoline: Photoinduced Tautomerization and Solvation Effects". The Journal of Physical Chemistry B. 101 (39): 7786–7793. doi:10.1021/jp971293u.

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